Synonyms: a cofactor F420
|Superclasses:||a cofactor → a prosthetic group|
One of the distinguishing features of methanogenic bacteria is their blue-green fluorescence when irradiated with UV light. This fluorescence is due to F420, a cofactor that was identified on the basis of this feature. This compound, named for its intense absorbance at 420 nm, was originally isolated by Cheeseman et al [Cheeseman72], and later identified by Eirich et al as the N-(N-L-lactyl-γ-L-glutamyl)-L-glutamic acid phosphodiester of 7,8-didemethyl-8-hydroxy-5-deazariboflavin 5'-phosphate [Eirich78].
The F420 biosynthetic pathway produces the intermediate F420-0, which contains no glutamate side chains. Glutamates are then added by several enzymes. F420 molecules isolated from different organisms differ in the number of the glutamate molecules in the side chains, as well as the nature of the bond (which could be either α or γ) [Li03a, Graupner03, Choi01].
Choi01: Choi KP, Bair TB, Bae YM, Daniels L (2001). "Use of transposon Tn5367 mutagenesis and a nitroimidazopyran-based selection system to demonstrate a requirement for fbiA and fbiB in coenzyme F(420) biosynthesis by Mycobacterium bovis BCG." J Bacteriol 183(24);7058-66. PMID: 11717263
Li03a: Li H, Xu H, Graham DE, White RH (2003). "Glutathione synthetase homologs encode alpha-L-glutamate ligases for methanogenic coenzyme F420 and tetrahydrosarcinapterin biosyntheses." Proc Natl Acad Sci U S A 100(17);9785-90. PMID: 12909715
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